diff --git a/software/firmware/source/SoftRF/src/driver/AudioVario.cpp b/software/firmware/source/SoftRF/src/driver/AudioVario.cpp
new file mode 100644
index 000000000..6312a8811
--- /dev/null
+++ b/software/firmware/source/SoftRF/src/driver/AudioVario.cpp
@@ -0,0 +1,78 @@
+/*
+ * AudioVario.cpp
+ * Copyright (C) 2016-2021 Linar Yusupov
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "AudioVario.h"
+#include "../system/SoC.h"
+#include "EEPROM.h"
+
+/*
+  10 knots = 10 nautical miles/hour = 60761.2 feed / 3600 sec = 16.88 feet/s
+*/
+#define MAX_VS 16.88 /* feet/s = 10 knots */
+#define UPDATE_PERIOD 2000
+#define FAST_ONE_CYCLE 75
+#define SLOW_ONE_CYCLE 1000
+
+static unsigned long AudioVarioTimeMarker = 0;
+static const int freq_array[] = {
+  50, 100, 200, 640, 1040, 3000, 3500
+};
+#define CLIMB_START 2
+#define DEAD_BAND 0.2
+
+static bool turned_on = false;
+
+void Audio_Vario(double vs)
+{
+  unsigned long t = millis();
+  unsigned long lapse = t - AudioVarioTimeMarker;
+  const int max_freq_index = (sizeof(freq_array) / sizeof(freq_array[0]))
+    - 1 - CLIMB_START;
+  static int one_cycle = SLOW_ONE_CYCLE, freq_index = 0,
+    on_period = 1000 / (freq_array[CLIMB_START] / 20);
+  int hz;
+
+  if (vs > MAX_VS)
+    vs = MAX_VS;
+
+  if (vs < DEAD_BAND) /* below than dead band */
+    hz = 0;
+  else {
+    one_cycle =
+      (SLOW_ONE_CYCLE - FAST_ONE_CYCLE) * ((MAX_VS - vs) / MAX_VS)
+      + FAST_ONE_CYCLE;
+
+    /* map vs to freq_index */
+    freq_index = max_freq_index * vs / MAX_VS + CLIMB_START;
+    hz = freq_array[freq_index];
+    on_period = 1000 / (hz / 20); /* need 20 pulses */
+  }
+
+  if (hz > 0 && lapse < on_period) {
+    if (!turned_on) {
+      SoC->Sound_tone(hz, settings->volume);
+      turned_on = true;
+    }
+  } else {
+    SoC->Sound_tone(0, settings->volume);
+    turned_on = false;
+  }
+
+  if (lapse > one_cycle)
+    AudioVarioTimeMarker = t;
+}
diff --git a/software/firmware/source/SoftRF/src/driver/AudioVario.h b/software/firmware/source/SoftRF/src/driver/AudioVario.h
new file mode 100644
index 000000000..3109d7d5e
--- /dev/null
+++ b/software/firmware/source/SoftRF/src/driver/AudioVario.h
@@ -0,0 +1,24 @@
+/*
+ * AudioVario.h
+ * Copyright (C) 2016-2021 Linar Yusupov
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef AUDIOVARIO_H
+#define AUDIOVARIO_H
+
+void Audio_Vario(double vs);
+
+#endif /* AUDIOVARIO_H */
diff --git a/software/firmware/source/SoftRF/src/driver/Sound.cpp b/software/firmware/source/SoftRF/src/driver/Sound.cpp
index aa4db95ab..74517f696 100644
--- a/software/firmware/source/SoftRF/src/driver/Sound.cpp
+++ b/software/firmware/source/SoftRF/src/driver/Sound.cpp
@@ -51,10 +51,13 @@ bool Sound_Notify(void)
 
 void Sound_loop(void)
 {
-  if (SoundTimeMarker != 0 && millis() - SoundTimeMarker > ALARM_TONE_MS) {
-    SoC->Sound_tone(0, settings->volume);
-    SoundTimeMarker = 0;
-  }
+  if (SoundTimeMarker != 0) { /* Sound_Notify */
+    if (millis() - SoundTimeMarker > ALARM_TONE_MS) {
+      SoC->Sound_tone(0, settings->volume);
+      SoundTimeMarker = 0;
+    }
+  } else /* Audio Vario */
+    Audio_Vario(ThisAircraft.vs);
 }
 
 void Sound_fini(void)
diff --git a/software/firmware/source/SoftRF/src/driver/Sound.h b/software/firmware/source/SoftRF/src/driver/Sound.h
index b26602abd..b8e56df25 100644
--- a/software/firmware/source/SoftRF/src/driver/Sound.h
+++ b/software/firmware/source/SoftRF/src/driver/Sound.h
@@ -19,6 +19,8 @@
 #ifndef SOUNDHELPER_H
 #define SOUNDHELPER_H
 
+#include "AudioVario.h"
+
 #define ALARM_TONE_HZ     1040
 #define ALARM_TONE_MS     1000
 
diff --git a/software/firmware/source/SoftRF/src/platform/ESP32.h b/software/firmware/source/SoftRF/src/platform/ESP32.h
index 0cf33b99c..df40e522a 100644
--- a/software/firmware/source/SoftRF/src/platform/ESP32.h
+++ b/software/firmware/source/SoftRF/src/platform/ESP32.h
@@ -102,7 +102,7 @@ extern Adafruit_NeoPixel strip;
                                   SOC_UNUSED_PIN))
 
 #define SOC_GPIO_PIN_BUZZER   (hw_info.model != SOFTRF_MODEL_PRIME_MK2 ?\
-                                13 : SOC_UNUSED_PIN)
+                                13 : 14)
 
 /* SPI (does match Heltec & TTGO LoRa32 pins mapping) */
 #define SOC_GPIO_PIN_MOSI       27